Duane M Wulf

Interests

Research

Research is perhaps the most exciting segment of the academic world since the researcher is extending the boundaries of human knowledge. The broad definition of my research interests would be Meat Production and Meat Quality. The current meat marketing system in the USA encourages the production of overly-fat animals because higher fat content is related to improved meat palatability. Animals that have an excess of fat deposition are less efficient, requiring a higher amount of natural resources and having greater environmental impact than animals with an optimal level of fat deposition. In addition, meat products with higher levels of saturated fat are related to increased risk of cardiovascular disease among humans. Therefore, I am interested in improving meat quality using methods that don’t require excess fat production. Methods to improve meat quality have the potential to change market signals within the meat industry, resulting in lowered environmental impact and improved human health worldwide.Specifically, my research interests include:• Sustainability of meat production systems.• Early-postmortem glycolysis and pH decline effects on meat quality.• Methods of improving meat quality (antemortem and postmortem).• Increasing the utilization of low-value meat products.• Cultural differences in meat consumption, meat processing, and carcass utilization.I consider myself an applied researcher; however, I am very keen to the possibility of collaborating with basic scientists as I have in the past. If scientists are willing to learn from each other and work together, it provides the opportunity to make significant impact through a systems approach to solving the world’s problems.I also need to keep in mind that the citizens of Arizona are providing me with a research grant every year by paying of portion of my salary and expenses. I will make sure that the results of my research with provide a direct or indirect benefit to these tax payers.

Teaching

I believe that teaching is one of the most rewarding things a person can do during their lifetime. Zig Ziglar said, "You can get everything out of life that you want, if you just help enough other people get what they want", and I am convinced that this is true. During my teaching experiences, I have witnessed students who were transformed from a "nobody" into a "somebody". The teacher's primary responsibilities are to instill interest in the subject matter and confidence in the student. If the teacher is effective, the students will teach themselves. I believe that in order to stimulate students' curiosity, you must not only teach the "who, what, when, where and how", but also the "why", which I feel is much more interesting. A teacher must also be open-minded to the vast differences among students with regard to their backgrounds, interests, aspirations and, most importantly, learning styles. Important concepts that I keep in mind when designing a course:• Effective learning is more about what the student does and less about what the teacher does.• Students will only retain 10 to 50 percent of the subject matter presented in a course, so it better be the most important 10 to 50 percent.• Much of the information may be out-dated in the near future; hence, a teacher must teach the students that learning is a life-long process and must instruct them on how to learn.• Cultures across the globe have different manners of production, business, cooking, etc., but the anatomy, biology and chemistry remains the same. Therefore, I should focus more on teaching the basic foundations. I.e., I should teach basic muscle and skeletal anatomy more that making students memorize meat cut names.• Today’s students have the entire world's knowledge at their fingertips, but we need to teach them how to understand it, decipher it, and apply it.

Courses

Scholarly Contributions

Journals/Publications

• Waller, B. E., Garcia, S. R., Fuerniss, L. K., Johnson, B. J., Woerner, D. R., & Wulf, D. M. (2023). Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on muscle fiber type, live performance, carcass characteristics, and boxed beef and retail cut yields. Journal of animal science, 101.
  More info

  Producer live performance data and carcasses from steers (n = 116) resulting from the mating of four Limousin/Angus sires heterozygous for the F94L myostatin mutation to Jersey/Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on live performance, carcass traits and USDA grades, and boxed beef and retail yields. Slaughter data were collected at time of harvest and carcass data were collected 48 hours postmortem. One side from each of the 58 carcasses was fabricated into boxed beef and retail cuts by experienced lab personnel 5-8 d postmortem. One copy of the F94L allele did not affect gestation length, birth weight, percentage of unassisted births, feedlot average daily gain, live weight at harvest, hot carcass weight, or dressing percentage (P > 0.05). Muscle fiber analysis indicated that the increase in muscularity by the F94L allele in the semitendinosus and longissimus was likely due to hyperplasia as there was a 19% increase in the quantity of myosin heavy chain type IIA and IIX fibers in the semitendinosus (P  0.05). Carcasses from steers with one F94L allele had larger ribeye areas (99.2 vs. 92.3 sq.cm.), greater ribeye width:length ratios (0.498 vs. 0.479), lower USDA yield grades (2.21 vs. 2.66), and lower marbling scores (438 vs. 480) (P 
• Waller, B. E., Whitewood, T. A., Woerner, D. R., Garcia, S. R., & Wulf, D. M. (2023).

  Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on strip loin steak dimensionality, shear force, and sensory attributes

  . Journal of Animal Science, 101. doi:10.1093/jas/skad325
• Waller, B. E., Whitewood, T. A., Woerner, D. R., Garcia, S. R., & Wulf, D. M. (2023). Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on strip loin steak dimensionality, shear force, and sensory attributes. Journal of animal science, 101.
  More info

  Carcasses (n = 115) from steers resulting from the mating of four Limousin × Angus sires heterozygous for the F94L myostatin mutation to Jersey, Jersey × Holstein, and Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on strip loin dimensionality, Warner-Bratzler shear force and slice shear force, and sensory panel ratings. In phase I of a two-phase study, 57 carcasses from two sires were utilized to obtain samples of longissimus dorsi (LD), psoas major (PM), gluteus medsius (GM), semitendinosus (ST), serratus ventralis, triceps brachii, and biceps femori muscles, which were vacuum packaged, aged until 10 d postmortem, and frozen. Frozen strip loins were cut into 14, 2.5-cm-thick steaks each, and individual strip loin steaks were imaged at a fixed height on a gridded background and processed through image analysis software. In phase II, to obtain a greater power of test for LD palatability attributes, 58 additional carcasses from three sires were utilized to obtain LD samples only for sensory panel and shear force analysis. Cooked steak sensory attributes evaluated by trained panelists were tenderness, juiciness, beef flavor, browned flavor, roasted flavor, umami flavor, metallic flavor, fat-like flavor, buttery flavor, sour flavor, oxidized flavor, and liver-like flavor. In strip loin steaks from carcasses with one F94L allele, LD muscle area was larger in steaks 4, 5, 7, 8, and 9, and steaks 1, 6, 7, and 9 were less angular than those from carcasses with no F94L allele (P < 0.05). Of the seven muscles observed, there were no shear force differences between F94L genotypes (P > 0.20). F94L genotype did not affect sensory panel ratings of LD and GM steaks (P > 0.07). Cooked ST steaks from carcasses with one F94L rated lower in fat-like flavor compared to those from carcasses with no F94L allele (P = 0.035). Cooked PM steaks from carcasses with one F94L allele rated lower in juiciness, fat-like flavor, buttery flavor, and umami flavor compared to those with no copies of the F94L (P < 0.04). In summary, one copy of the F94L allele utilized in beef × dairy cross steers improved strip loin steak dimensionality, did not affect cooked steak tenderness across seven muscles, and decreased fat-associated flavors in the PM and ST. The use of F94L homozygous terminal beef sires would be an easily implemented strategy for dairy producers to improve steak portion size and shape in carcasses from nonreplacement calves.
• Daniel, J. A., Held, J. E., Brake, D. G., Wulf, D. M., & Epperson, W. B. (2006). Evaluation of the prevalence and onset of lung lesions and their impact on growth of lambs.. American journal of veterinary research, 67(5), 890-4. doi:10.2460/ajvr.67.5.890
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  To determine the prevalence and temporal onset of lung lesions in lambs and the impact of lung lesions on growth of affected lambs..259 crossbred wether lambs from a single flock in the upper Midwestern United States..An observational study was conducted. Lambs born in the spring and fall were slaughtered at finished weight or at a predetermined time point. Lungs of each lamb were examined and classified as normal, moderate lesions (consolidation > 5% but < or = 50% of any lobe), or severe lesions (consolidation > 50% of any lobe). Data were examined to detect effects of prevalence or severity of lung lesions on growth and carcass traits..57 of 89 (64%) spring-born lambs had lung lesions characterized by consolidation of lung tissue. A small number of lambs had pulmonary adhesions or active abscesses. In contrast, only 31 of 108 (29%) fall-born lambs had lung lesions. Severe lung lesions were associated with a significant reduction in average daily gain. Severe lung lesions were not detected until the middle of the finishing period and were associated with culture of Mannheimia haemolytica or Pasteurella multocida..Analysis of results indicates that the prevalence of severe lung lesions can be quite high in lambs. Severe lung lesions can lead to greatly decreased growth performance of lambs.

Presentations

• Wulf, D. M. (2023). Arizona Initiative for Arid Lands Animal Production. Arizona Cattle Growers Annual ConventionArizona Cattle Growers Association.
• Wulf, D. M. (2023). Arizona Initiative for Arid Lands Animal Production. Greenlee County Cattle Growers Annual Meeting.
• Wulf, D. M. (2023). Capturing Beef Cutability: A Collaborative Approach to Addressing Red Meat Yield. Reciprocal Meat Conference. St. Paul, MN: American Meat Science Association.
• Wulf, D. M. (2023). Predicting Red Meat Yield in Beef Carcasses. NCBA Red Meat Yield Roundtable. Denver, CO: National Cattlemen's Beef Association.
• Wulf, D. M. (2023). The Future of Beef and UA's Animal Science Program. Yavapai County Cattle Growers Annual Meeting.
• Wulf, D. M. (2023). Understanding Carcass Value. Mohave County 4-H Carcass Show.
• Wulf, D. M. (2022, March). Help or Hindrance? Which career paths benefit from a graduate degree, and which are unaffected.. American Meat Science Assoc. Student Webinar SeriesAmerican Meat Science Association.
  More info

  Wulf, Duane M. 2022. “Help or Hindrance? Which Career Paths Benefit from a Graduate Degree, and Which Are Unaffected.” American Meat Science Assoc. Student Webinar Series. March.
• Wulf, D. M. (2021, March). Factors affecting Beef Carcass Value. Arizona Range Livestock Symposium.
• Wulf, D. M. (2021, May). Meat Product Ingredients. AZ/NM Meat Processor Short CourseFarm Bureau.

Other Teaching Materials

• Wulf, D. M. (2023. Beef Harvest and Carcass Fabrication Short Course. University of Arizona.

Others

• Wulf, D. M., Garcia, S. R., & Diaz, D. (2020, May). How to Butcher a Pig (On Farm Pig Harvest Procedures). YouTube. https://www.youtube.com/watch?v=ojctijm2Tgo
  More info

  Due to COVID shut downs at several pork processing plants, there was much demand for science-based procedures for on-farm pig harvest. This video was produced and published with the support of the National Pork Board.